Wiring nightmare after small engine fire

Boooosted strangler

Boooosted strangler

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OK so I recently had a header cracked which ultimately started a small fire that caught insulation on my engine sensors wires on fire...mine is a 97 tj manual 4.0, I bought a used 98 manual 4.0 wiring harness and the connectors were mostly the same but 4 different ...now I cross reference all the wire color I could and connected my connectors to it..I now crank it the starter does its thing but it won't fire I'm just at my end...any ideas?? Or am I just s.o.l.
 
Noid lights on the injectors to confirm injectors pulsing?

Spark plug test light off the coil or on a cylinder to confirm firing?

Any codes?

Oil pressure gauge working?

Headlights work?

Check grounds. Fuses?

-Mac
 
What is the build date on your 97 TJ. From everything I have read and also been able to verify TJ's with a build date of 01/-03/96 had some wires different than later models and don't match the wiring diagram/color colors in the FSM.

And of course I have a 01/976 TJ also.

Also crank sensor is a lot of times the issue with a crank no fire problem.
 
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My crank sensor is new, the build Date is 06/97 so I was hoping like hell mine fell in the later date ones but apparently it didn't like 90% of the connectors were the same but I had to change over the 2 bigger ones ,nor the ecu but the bigger ones just after the ecu , my coil , the throttle poss, and the o2, I need to double check under it I think the speedo plug was wrong , my speedo didn't work before so I said screw it but maybe I need the connector on there...
 
It is extremely frustrating because after a loooooong road of trying to get that thing driving straight, and a long list of issues with the turbo and getting it dialed it I had that this running freaking awesome I'm talking 85 on the highway going straight on 37s with alot more ass behind it, and then the header cracked and It had a small fire
 
No codes , all the grounds are freshly wire wheeled and or new wire everywhere, I do need to test the spark and f.i. but I have never done it before I can ask some of the sparkys at work to show me , I have a nice klien multimeter just don't know what to set it all on for what test and what not
 
Does anyone know where to get a new wire harness for an early 97 ??? I can't find a new one anywhere that's why I went with an ebay special and got a special shaft in the box to sit on and think about how bad of a decision that was
 
I've got a 97 too...pm me if you want a video call and I can show you what mine looks like.

I don't know of anyone producing a commercially available harness. Painless usually is my go too.

I've been chasing random misfire codes and have replaced a lot of stuff and checked the harness...but I think I am down to pulling the engine harness completely out and inspecting every inch.

-Mac
 
Some of the 97 connectors are build date related and others are plain 97 vs 98+. The speed sensor in 97 was the same no matter what day the 97 was produced. It came from the 92-95 YJ. That sensor was known for ATF from the transfer case leaking it's way up into the wiring, so they redesigned it for 98. The new speed sensor was 98+. If you wish to get the speed sensor working, you can easily purchase the 98+ sensor and they usually come with a pigtail for you to splice in place of the old one. Easy work. A speed sensor will not keep you from starting, however. But it will affect how your Jeep idles and can cause the engine to shut off and throw a code sometimes. So I would say fix it.

Tail lights are another example of 97 vs 98+, not that they have anything to do with this problem. Other sensors like the crank, TPS, possibly IAC and a few others I believe used YJ sensors in early 97 and in late 97 switched to new sensors that the other years continued to use also.

Can you give more info on which connectors did not match up and how you wired them? I'm not sure wire color would necessarily be an entirely accurate way to hook them up.. I have seen a decent number of known wires and their functions not match the color the factory service manual said they would be....on 100% factory harnesses. Like they ran out of wire or something and subbed in other colors to keep up production for the day. so I am wondering if one of the connections you made is not right.

What all did the harness replacement bring with it? A new PDC? Did you only change the engine harness? If it brought a PDC with it, is the PDC in good shape and all terminals underneath still popped into place for the relays and fuses that connect to them? I've had some tough luck with used old replacement harnesses so definitely need to make sure all is well with it before just slapping it in and plugging it up, unfortunately.
 
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Since you have a later built 97 TJ my suggestion for finding a wiring harness is just doing a search like you've done. I was able to get a used early build off Ebay.

Macho makes the suggestions and answering his question might help us diagnose a bit more.
 
The sensors I spliced in was the TPS, Oil pressure, and the coil connector , and yes the wire color some were different some the same...I did my best to go from the yj color which most of mine were originally and the tj color I ended up with , I lined up the other 2 bigger connectors as best as I could and crossed refer colors...when my wife gets home I'm going to test for spark off the coil, then test the connectors off the injectors as well...thank you guys by the way!!! I really do appreciate you taking the time to help my dumbest...I just obsess over it until I get it running and I'm talking bad!!! The more time and money I put in the worse I obsess...it's hard when it's down because my son is soooo proud when we are in it , and it don't get any better than that for me!!! He loves the attention this thing brings, me personally I don't like the attention but it's about him...everyone around here freaks about this thing, overkill is an understatement on it so thank you if I can get this thing back running I will get more than 3 hours of sleep a night and not walk around in a daze trying to figure out what to do next to fix it
 
Boooosted strangler said:
The sensors I spliced in was the TPS, Oil pressure, and the coil connector , and yes the wire color some were different some the same...I did my best to go from the yj color which most of mine were originally and the tj color I ended up with , I lined up the other 2 bigger connectors as best as I could and crossed refer colors...when my wife gets home I'm going to test for spark off the coil, then test the connectors off the injectors as well...thank you guys by the way!!! I really do appreciate you taking the time to help my dumbest...I just obsess over it until I get it running and I'm talking bad!!! The more time and money I put in the worse I obsess...it's hard when it's down because my son is soooo proud when we are in it , and it don't get any better than that for me!!! He loves the attention this thing brings, me personally I don't like the attention but it's about him...everyone around here freaks about this thing, overkill is an understatement on it so thank you if I can get this thing back running I will get more than 3 hours of sleep a night and not walk around in a daze trying to figure out what to do next to fix it
Click to expand...

Any chance you got some wires crossed when you spliced them in?
Also check all your grounds as they are a PITA.
I have a V-8 swap in mine so I know about the headache of getting stuff wired correctly.

IAC is the Idle Air Control.
 
Let's take a step back. First, this is a problem that is easily overcome. So while I know you are frustrated, don't let it get to you. The solution to getting your vehicle running just the way it was before is simple, but time consuming.

1. Go get the two repair manuals that you need - 97 and 98.

2. You need to go connector by connector through the two harnesses and confirm that each wire is correct per the manual. In other words, if Connector 1, Position 1 is red in the book, make sure it is red in your hand. Once you've confirmed that, then you know you have the proper manual to support the next step. The colors should match, but if they don't, we don't really care. What we want to confirm is that you have a harness that has a wire in each location that you should have one in, AND YOU WANT TO CHECK BOTH ENDS. So if C1/P1 is supposed to be red and connected to C2/P1, but is actually blue but still connected properly, then just note the new wire color and move on. If C1/P1 ISN'T connected to C2/P1, then you have the wrong manual for that harness, so get the right manual.

3. You now need to compare the 2 manuals. In other words, if Connector 1, Position 1 is XYZ function in the 97, the you need to confirm that Connector 1, Position 1 is XYZ function in the 98 as well. This should literally take you 15 minutes as I suspect you will find that they are almost all identical. Note that this is a PAPER exercise - we're NOT doing this with the actual harness.

4. Make any adjustments that are required to your '98 harness. You will do this based on the PAPER exercise you did in step 3 above.

This probably seems like a lot of work, but here is the #1 thing I can tell you: you can NOT match harnesses up based on wire color. You can start there, but that is absolutely a recipe for disaster, and frankly, doesn't matter. What matters is the two ends are connected to where they need to be. There are a lot of reasons why a harness might have a different color wire in a different place. The number one cause is that the supplier ran out of that color wire for that particular production run. Good news, wire color doesn't matter (except to make life easier). Better news - as long as you have the right size wire connected to the right place on both ends, you'll be fine.

I get it - there are a lot of wires and a lot of connectors. Don't sweat it - your harness will be 90% the same between model years in all likelihood, so this exercise will be quick. But again, and I can't stress this enough, do NOT connect wires to each other just because they are the same color.

d-
 
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I have traced just about every wire for wire the only thing I'm stumped on is there is a spliced red and light green tracer that I can't find where it should go off the old connector everything else I traced to their home, but I just spliced in my speed sensor and it sounded better but the volts are dropping hard as I crank now and if I leave the key on for a min it dings and the volt meter drops off after the beep or ding
 
Boooosted strangler said:
I have traced just about every wire for wire the only thing I'm stumped on is there is a spliced red and light green tracer that I can't find where it should go off the old connector everything else I traced to their home, but I just spliced in my speed sensor and it sounded better but the volts are dropping hard as I crank now and if I leave the key on for a min it dings and the volt meter drops off after the beep or ding
Click to expand...

where are we talking about? There is a very important red with light green tracer wire that goes from the computer to the massive connector array under dash, near where the headlight switch is. It's connector C106. it also runs behind the dash and over to the glove box fuse panel. The circuit is F12, and it is part of lots of the "turn on" circuits like the fuel pump & ASD relay.

I also have a 97 and I found this particular wire to be melted behind the dash thanks to some clever "wiring tricks" by the previous owner.


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Is that the fuse box behind glove box or is that the one by the battery?? Also where did you get the connector layout page I can't find that that would be super helpful!! Thank you so much!!! I'm feeling more hopeful now
 
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